This invention is generally directed to developer compositions, and more specifically, the present invention relates to developer compositions with coated carrier components, or coated carrier particles that can be prepared by, for example, dry powder processes. More specifically, the present invention relates to compositions, especially carrier compositions comprised of a core and thereover terpolymers, for example terpolymers of styrene, an olefin, especially a diolefin, and an alkyl amine methacrylate or acrylate.
In embodiments of the present invention, the carrier particles are comprised of a core with a coating thereover of terpolymers, such as terpolymers of styrene, butadiene and dimethylaminoethyl methacrylate, terpolymers of styrene, butadiene and alkyl aminoethyl methacrylates or acrylates with alkyl amine groups higher in carbon chain length than methyl, such as t-butylaminoethyl methacrylate, diethylaminoethyl methacrylate, diisopropylaminoethyl methacrylate, and the like. The carrier may include the polymer coating thereover in admixture with other suitable polymers, and more specifically, with a suitable known second polymer, such as a fluoropolymer, polymethylmethacrylate, poly(urethane), especially a crosslinked polyurethane, such as a poly(urethane)polyester and the like, and moreover, the polymer coating may contain a conductive component, such as carbon black, and which conductive component is preferably dispersed in the polymer coating. With the conductive component, there is enabled carriers with increased developer triboelectric response at relative humidities of from about 20 to about 90 percent, improved image quality performance, excellent high conductivity ranges of from about 10.sup.-10 to about 10.sup.-7 (ohm-cm).sup.-1, a triboelectrical charge, for example a carrier tribo range of from about a plus (positive charge) 50 to about 150, or to about 95 microcoulombs per gram, and preferably from about a positive 55 to about a positive 90 microcoulombs per gram, and most preferably from a positive about 60 to a positive about 70 microcoulombs per gram.
The carrier particles of the present invention can be selected for a number of different xerographic copiers and printers, such as high speed color xerographic copiers, printers, digital copiers, and more specifically, wherein colored copies with excellent image resolution and substantially no background deposits are achievable in copiers, printers, digital copiers, and the combination of xerographic copiers and digital systems. Developer compositions comprised of the carrier particles illustrated herein and prepared, for example, by a dry coating process are generally useful in electrostatographic or electrophotographic imaging systems, especially xerographic imaging and printing processes, and digital processes. Additionally, the invention developer compositions comprised of substantially conductive carrier particles are useful in imaging methods wherein relatively constant conductivity parameters are desired. Furthermore, in the aforementioned imaging processes the triboelectric charge on the carrier particles can be preselected depending on the polymer composition and dispersant component applied to the carrier core, and the type and amount of the conductive component selected.